Rotating Electric Machine Through Bolt Configuration
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Solution Overview
Problem
Conventional rotating electric machines for power steering devices face issues with size and misalignment due to the use of two through bolts, leading to uneven axial force distribution and increased airgap between the rotor and stator, which reduces output and makes them prone to deformation and breakage under vehicle vibrations.
Innovation Solution
The design incorporates three or more through bolts evenly spaced around the circumference of the base cap and end cap, reducing the axial force on each bolt and ensuring even distribution, which minimizes the airgap and enhances coaxial alignment, thereby increasing output and reducing the risk of deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If two through bolts are used to fasten the front and rear end caps, then the device complexity is reduced, but the axial force on each bolt increases causing greater bolt diameter and larger overall machine size
Solution Approach 1:
The fastening function is segmented from a single fastening point to multiple distributed fastening points (three or more through bolts), distributing the axial force and reducing the load on each individual bolt, thereby allowing smaller bolt diameters and reduced overall machine size
2Device complexity
If two through bolts are used to fasten the front and rear end caps, then the device complexity is reduced, but the axial force distribution becomes uneven causing misalignment and increased airgap
Solution Approach 1:
The fastening function is segmented to multiple distributed fastening points that evenly distribute axial force around the circumference, ensuring uniform compression and precise coaxial alignment between front and rear end caps, thereby reducing airgap and improving manufacturing precision
3Reliability
If the flanges are reinforced to prevent deformation and breakage under vibration, then the reliability is improved, but the front and rear end caps become larger increasing the overall machine volume
Solution Approach 1:
The stress concentration problem is resolved by segmenting the fastening to multiple distributed points, which evenly distributes vibrational stress across the flange structure. This eliminates the need for excessive flange reinforcement, maintaining reliability while keeping the end cap size compact
Data Source
AI summary
A rotating electric machine for driving a drive object is provided. The rotating electric machine includes a motor case, a stator, a winding, a rotor, a shaft, a base cap, an end cap, an output rod, base cap holes, end cap holes, and through bolts. The base cap has base cap flanges formed on a circumferential edge and extending radially-outward beyond an outer wall of the motor case. The end cap has end cap flanges formed on a circumferential edge and extending radially-outward beyond the outer wall of the motor case. Base cap holes are formed on the base cap flanges and end cap holes in axial alignment with the base cap holes are formed on the end cap flanges. Through bolts fasten the base cap flanges to the end cap flanges.